Phase-separated composition comprising two miscible solvents, and use thereof in a process for making capsules

ABSTRACT

The invention relates phase-separated compositions comprising two miscible solvents. More specifically, the invention relates to compositions comprising liquid droplets of an internal phase comprising a solvent B and further compounds, said droplets being dispersed in an external phase comprising solvent A, wherein solvent A and solvent B are miscible. Such compositions find use in various technical fields, including encapsulation, vectorisation, protection of compounds, separations, and chemical reactions in a dispersed medium.

BACKGROUND OF THE INVENTION

[0001] The invention relates phase-separated compositions comprising twomiscible solvents. More specifically, the invention relates tocompositions comprising liquid droplets of an internal phase comprisinga solvent B and further compounds, said droplets being dispersed in anexternal phase comprising solvent A, wherein solvent A and solvent B aremiscible. Such compositions find use in various technical fields,including encapsulation, vectorisation, protection of compounds,separations, and chemical reactions in a dispersed medium.

[0002] The invention also relates to a process for making capsules, oreven multiple capsules, wherein such a composition is used. This processis simple, cost effective, and/or offers a new solution forencapsulating, vectorising, or protecting some compounds.

[0003] Various kinds of dispersions of objects in a liquid medium havebeen used for years. Various kinds of dispersions of objects in a liquidmedium have been described in references. Dispersions of solid particlesof various sizes in water are often referred to as particle dispersionsor colloidal dispersions. Dispersions of droplets of a first liquidphase in a second liquid external phase, wherein the two phases are notmiscible, are usually referred to as emulsions (if energy is added) ormicroemulsions (if the system is at a thermodynamical equilibrium). Useof dispersing agents or stabilizing agents, such as surfactants oramphiphilic copolymers, is known.

[0004] Dispersions of objects such as capsules are also known. Capsulesare objets comprising a shell either empty or comprising inside at leastone internal phase and/or additive (core). Examples of capsulesdispersions include dispersions in water of vesicles comprising a corebeing an aqueous phase, and a shell being a membrane consisting of twoorganized layers of amphiphilic compounds comprising a hydrophilicmoiety and a hydrophobic moiety. In vesicles, the hydrophobic moiety ofone of the layers faces the hydrophobic moiety of the other layer.

[0005] The dispersions as described above find use in many fields.Examples include encapsulation, vectorisation and/or protection ofcompounds, for said compounds to be released, protected, and/or providedin an incompatible environment. Examples include also chemicaltransformations in a phase separated system, inside a dispersed objector at an interface. Examples include also separations of compoundsand/or recovery of compounds. There is a need in enriching the art withdispersions comprising different phases and optionally furthercompounds, in different concentrations. There is also a need inproviding products for reinforcement, strengthening, and/ormodifications of mechanical properties of materials, such as elastomersor thermoplastics.

[0006] In preparing dispersions, multiblock copolymers have proved to beuseful. Recent references teach the use of diblock copolymers for makingvesicles. For example Discher et al. describe usingpolyphenyleneoxide-polyethylethylene [EO]₄₀-[EE]₃₇ block copolymers, inSCIENCE, may 1999, page 1143. They teach that using block copolymersallows controlling some properties of the membrane, such as mechanicalproperties. Yu et al. in Langmuir, 1999, 15, 7157-7167 describe usingpolystyrene-polyethyleneoxide block copolymers, and controlling themembrane structure. Shen et al. in J. Phys. Chem. B 1999, 103. 9473-9487describe using polystyrene-polyacrylic acid [Styrene]₃₁₀-[AA]₅₂ blockcopolymers. Using polystyrene-polyacrylic acid block copolymers is alsodescribed by Yu et al. in Macromolecules, Vol 31, 1144-1154. Vesiclesmay be obtained by thin film rehydratation, or by adding water to ablock copolymer dispersed in a solvent (self-formation). Vesiclestructures are useful to encapsulate hydrophilic compounds.

[0007] In completely different objectives, it has been taught that twomiscible solvents can phase separate by adding a polymer. However, sucha phase separation does not result in a stable dispersion, and acollapse occurs.

BRIEF SUMMARY OF THE INVENTION

[0008] The invention relates to new dispersion structures that enrichthe art of dispersions and open a wide range of applications. Thus theinvention relates to a composition comprising at least two misciblesolvents, solvent A and solvent B, wherein the composition comprisesliquid droplets of an internal phase dispersed in an external liquidphase,

[0009] the droplets of the internal phase comprising:

[0010] solvent B,

[0011] a multiblock copolymer comprising at least two blocks, block Aand block B, wherein:

[0012] block A is soluble in solvent A and in solvent B,

[0013] block B is soluble in solvent B, and

[0014] block B is not soluble in solvent A,

[0015] optionally, solvent A, and

[0016] at least one additional compound being:

[0017] a linear polymer H, soluble in solvent B, and not soluble insolvent A, and/or

[0018] an additive being an active ingredient to be protected,vectorized or released with control, a reactive compound to betransformed by a chemical reaction, or a compound to be removed from aliquid phase,

[0019] the external liquid phase comprising solvent A, optionallysolvent B, and optionally an additive as mentioned above,

[0020] provided that the weight ratio (solvent B)/(solvent A+solvent B)in the droplets of the internal phase is greater than the weight ratio(solvent B)/(solvent A+solvent B) in the external phase.

[0021] In another aspect, the invention relates to a process forpreparing capsules wherein a said composition is used. The processinvolves reducing the ratio (solvent B)/(solvent A+solvent B), orremoving solvent B, for example by adding solvent A.

[0022] In another aspect, the invention relates to a solution useful forpreparing the composition, and therefore also useful for preparingcapsules.

DETAILED DESCRIPTION OF THE INVENTION

[0023] Definitions

[0024] In the present specification, the molecular weight of a polymer,copolymer or block refers to the weight-average molecular weight of saidpolymer, copolymer or block. The weight-average molecular weight of thepolymer or copolymer can be measured by gel permeation chromatography(GPC). In the present specification, the molecular weight of a blockrefers to the molecular weight calculated from the amounts of monomers,polymers, initiators and/or transfer agents used to make the said block.The one skilled in the art knows how to calculate these molecularweights. The ratios by weight between blocks refer to the ratios betweenthe amounts of the compounds used to make said blocks, considering anextensive polymerization.

[0025] Typically, the molecular weight M of a block is calculatedaccording to the following formula:${M = {\sum\limits_{i}{M_{i}*\frac{n_{i}}{n_{precursor}}}}},$

[0026] wherein M_(i) is the molecular weight of a monomer i, n_(i) isthe number of moles of a monomer i, and n_(precusor) is the number ofmoles of a compound the macromolecular chain of the block will be linkedto. Said compound may be a transfer agent or a transfer group, or aprevious block. If it is a previous block, the number of moles may beconsidered as the number of moles of a compound the macromolecular chainof said previous block has been linked to, for example a transfer agentor a transfer group. It may be also obtained by a calculation from ameasured value of the molecular weight of said previous block. If twoblocks are simultaneously grown from a previous block, at both ends, themolecular weight calculated according to the above formula should bedivided by two.

[0027] In the present specification, a unit deriving from a monomer isunderstood as a unit that may be directly obtained from the said monomerby polymerizing. Thus, a unit deriving from an ester of acrylic ormethacrylic acid does not encompass a unit of formula —CH—CH(COOH)—,—CH—C(CH₃)(COOH)—, —CH—CH(OH)—, —CH—C(CH₃)(OH)—, obtained for example bypolymerizing an ester of acrylic or methacrylic acid, or a vinylacetate, and then hydrolyzing. A unit deriving from acrylic acid ormethacrylic acid encompasses for example a unit obtained by polymerizinga monomer (for example an alkyl acrylate or methacylate) and thenreacting (for example hydrolyzing) to obtain units of formulaCH—CH(COOH)— or —CH—C(CH₃)(COOH)—. A unit deriving from vinyl alcoholencompasses for example a unit obtained by polymerizing a monomer (forexample a vinyl ester) and then reacting (for example hydrolyzing) toobtain units of formula —CH—CH(OH)— or —CH—C(CH₃)(OH)—.

[0028] Structure of the Composition, Capsules Obtained Therefrom

[0029] The composition according to the invention is a dispersion ofdroplets in an external phase. The external phase comprises solvent A,which is preferably water, and optionally solvent B. Usually itcomprises both. The droplets comprise solvent B, and other compounds:the multiblock copolymer, optionally some solvent A, and the additivecompound. The amount by weight of solvent B, relative to the amount ofsolvent A together with solvent B, in the droplets, is higher than theamount of solvent B in the external phase.

[0030] The composition is preferably at a thermodynamical equilibrium,with exchange and rearrangement of compounds at the interface of thedroplets, and between the phases. Conditions to have such an equilibriumusually depend on the solvents, and the multiblock copolymer (amounts,chemical structures . . . ). Upon removal, or partial removal, ofsolvent B, the equilibrium is broken, and a frozen structure isobtained. The droplets, when frozen, form capsules comprising a shell.Without intending to be bound to any theory, it is believed that theshell comprises the multiblock copolymer and optionally polymer H. BlockB and optionally polymer H, are not soluble in solvent A when solvent Bis removed. It is believed that they precipitate to form the shell. Thestep of removing or partially removing solvent B is also referred to asa quenching step. Removing, partially removing or quenching encompassesdiluting with solvent A, or adding solvent A, as the concentration ofsolvent B decreases when performing such a dilution or addition.

[0031] The composition may comprise an additive, dispersed or dissolvedin the droplets, and optionally also in the external liquid phase. Whenthe droplets are frozen, the additive is trapped inside the shell, andmay participate in forming a core inside the shell. The capsules usuallycomprise inside the shell an aqueous phase, if solvent A is water. Saidaqueous phase may comprise an additive. If there is no additive, theshell forms an empty capsule useful for example for reinforcement ofmaterials, for example for making light materials. Empty capsules mayalso encompass capsules comprising an aqueous phase inside the shell.

[0032] Solvents

[0033] Solvent A and solvent B are miscible. By miscible, it is meantthat they do not phase separate when mixed, without the multiblockcopolymer or the polymer H. Relative amounts of solvent A and solvent Bin the composition are such as solvent A and solvent B would not phaseseparate without the multiblock copolymer or the polymer H. Examples ofmiscible solvents useful for the invention include the following:

[0034] Water as solvent A and ethanol as solvent B, and

[0035] Water as solvent A and THF as solvent B.

[0036] Multiblock Copolymer

[0037] By multiblock copolymer, it is meant a copolymer comprising atleast two different blocks, block A and block B, linked together. Themultiblock copolymer may be linear sequenced copolymer, for example adi-block or a triblock copolymer. It may be a star-shaped copolymer, forexample a block copolymer comprising a core and branches, wherein thecore comprises one of the block, and the branches comprising the otherblock. It may be a grafted copolymer, comprising a backbone and graftslinked to the backbone, wherein the backbone comprises one of the block,and the branches comprising the other block. It is further mentionedthat the core, the backbone, the branches, and/or the grafts may becopolymers (random or block copolymers). Blocks may also be randomcopolymers. Examples of preferred linear sequences block copolymer are(block A)-(block B) diblock copolymers, (block A)-(block B)-(block A)triblock copolymers, and (block B)-(block A)-(block B) triblockcopolymers.

[0038] By linear polymer, it is meant a linear homopolymer, or a linearrandom copolymer, as opposed to a multiblock copolymer.

[0039] A block is usually defined by repeating units it comprises. Ablock may be a copolymer, comprising several kind of repeating units,deriving form several monomers. Hence, block A and block B are differentpolymers, deriving from different monomers, but they may comprise somecommon repeating units (copolymers). Block A and block B preferably donot comprise more than 50% of a common repeating unit (derived from thesame monomer).

[0040] Block A is soluble in solvent A and in solvent B. Block B issoluble in solvent B, and block B is not soluble in solvent A. Polymer His soluble in solvent B, and is not soluble in solvent A.

[0041] By block, polymer, or copolymer soluble in a solvent, it is meantthat the block, polymer or copolymer does not phase separatemacroscopically in said solvent at a concentration from 0,01% and 10% byweight, at a temperature from 20° C. to 30° C. By block, polymer, orcopolymer non soluble in a solvent, it is meant that the block, polymeror copolymer does phase separate macroscopically in said solvent at aconcentration from 0,01% and 10% by weight, at a temperature from 20° C.to 30° C. Solubility of a block refers to the solubility said blockwould have without the other block, that is the solubility of a polymerconsisting of the same repeating units than said block, having the samemolecular weight.

[0042] In a preferred embodiment, wherein solvent A is water, block A ishydrophilic and block B is hydrophobic. Hydrophilic or Hydrophobicproperties of a block refer to the property said block would havewithout the other block, that is the property of a polymer consisting ofthe same repeating units than said block, having the same molecularweight. By hydrophilic block, polymer or copolymer, it is meant that theblock, polymer or copolymer does not phase separate macroscopically inwater at a concentration from 0,01% and 10% by weight, at a temperaturefrom 20° C. to 30° C. By hydrophobic block, polymer or copolymer, it ismeant that the block, polymer or copolymer does phase separatemacroscopically in the same conditions.

[0043] It is further mentioned that the multiblock copolymer may besoluble in water, ethanol, THF, and/or in a hydrophobic compound.

[0044] Preferably, block B comprises repeating units deriving frommonomers selected from the group consisting of:

[0045] propylene oxide,

[0046] alkylesters of an alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monocarboxylic acid, such asmethylacrylate, ethylacrylate, n-propylacrylate, n-butylacrylate,methylmethacrylate, ethylmethacrylate, n-propylmethacrylate,n-butylmethacrylate, and 2-ethyl-hexyl acrylate, 2-ethyl-hexylmethacrylate, isooctyl acrylate, isooctyl methacrylate, lauryl acrylate,lauryl methacrylate,

[0047] vinyl Versatate,

[0048] acrylonitrile,

[0049] vinyl nitriles, comprising from 3 to 12 carbon atoms,

[0050] vinylamine amides, and

[0051] vinylaromatic compounds such as styrene.

[0052] Preferably, block A comprises repeating units deriving frommonomers selected from the group consisting of:

[0053] ethylene oxide,

[0054] vinyl alcohol,

[0055] vinyl pyrrolidone,

[0056] acrylamide, methacrylamide,

[0057] polyethylene oxide (meth)acrylate (i.e. polyethoxylated(meth)acrylic acid),

[0058] hydroxyalkylesters of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monocarboxylic acids, such as2-hydroxyethylacrylate, and

[0059] hydroxyalkylamides of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monocarboxylic acids,

[0060] dimethylaminoethyl (meth)acrylate, dimethylaminopropyl(meth)acrylate, ditertiobutylaminoethyl (meth)acrylate,dimethylaminomethyl (meth)acrylamide, dimethylaminopropyl(meth)acrylamide;

[0061] ethylenimine, vinylamine, 2-vinylpyridine, 4-vinylpyridine;

[0062] trimethylammonium ethyl (meth)acrylate chloride,trimethylammonium ethyl (meth)acrylate methyl sulphate, dimethylammoniumethyl (meth)acrylate benzyl chloride, 4-benzoylbenzyl dimethylammoniumethyl acrylate chloride, trimethyl ammonium ethyl (meth)acrylamido (alsocalled 2-(acryloxy)ethyltrimethylammonium, TMAEAMS) chloride,trimethylammonium ethyl (meth)acrylate (also called2-(acryloxy)ethyltrimethylammonium, TMAEAMS) methyl sulphate, trimethylammonium propyl (meth)acrylamido chloride, vinylbenzyl trimethylammonium chloride,

[0063] diallyldimethyl ammonium chloride,

[0064] monomers having the following formula:

[0065]

[0066] wherein

[0067] R₁ is a hydrogen atom or a methyl or ethyl group;

[0068] R₂, R₃, R₄, R₅ and R₆, which are identical or different, arelinear or branched C₁-C₆, preferably C₁-C₄, alkyl, hydroxyalkyl oraminoalkyl groups;

[0069] m is an integer from 1 to 10, for example 1;

[0070] n is an integer from 1 to 6, preferably 2 to 4;

[0071] Z represents a —C(O)O— or —C(O)NH— group or an oxygen atom;

[0072] A represents a (CH₂)_(p) group, p being an integer from 1 to 6,preferably from 2 to 4;

[0073] B represents a linear or branched C₂-C₁₂, advantageously C₃-C₆,polymethylene chain optionally interrupted by one or more heteroatoms orheterogroups, in particular O or NH, and optionally substituted by oneor more hydroxyl or amino groups, preferably hydroxyl groups;

[0074] alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monomers comprising a phosphate orphosphonate group,

[0075] alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monocarboxylic acids, such asacrylic acid, methacrylic acid

[0076] monoalkylesters of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, dicarboxylic acids,

[0077] monoalkylamides of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, dicarboxylic acids,

[0078] alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, compounds comprising a sulphonicacid group, and salts of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, compounds comprising a sulphonicacid group, such as vinyl sulphonic acid, salts of vinyl sulfonic acid,vinylbenzene sulphonic acid, salts of vinylbenzene sulphonic acid,alpha-acrylamidomethylpropanesulphonic acid, salts ofalpha-acrylamidomethylpropanesulphonic acid 2-sulphoethyl methacrylate,salts of 2-sulphoethyl methacrylate, acrylamido-2-methylpropanesulphonicacid (AMPS), salts of acrylamido-2-methylpropanesulphonic acid, andstyrenesulfonate (SS).

[0079] Block A more preferably comprises units deriving from monomersselected from the group consisting of:

[0080] acrylic acid, methacrylic acid,

[0081] acrylamide, methacrylamide,

[0082] vinyl sulphonic acid, salts of vinyl sulfonic acid,

[0083] vinylbenzene sulphonic acid, salts of vinylbenzene sulphonicacid,

[0084] alpha-acrylamidomethylpropanesulphonic acid, salts ofalpha-acrylamidomethylpropanesulphonic acid

[0085] 2-sulphoethyl methacrylate, salts of 2-sulphoethyl methacrylate,

[0086] acrylamido-2-methylpropanesulphonic acid (AMPS), salts ofacrylamido-2-methylpropanesulphonic acid, and

[0087] styrenesulphonate (SS).

[0088] While block B is usually a neutral block, block A might bediscriminated as regard to its electrical behavior or nature. It meansthat block A may be a neutral block, or a polyionic block (a polyanionicblock, or a polycationic block). It is further mentioned the electricalbehavior or nature (neutral, polyanionic or polycationic) may depend onthe pH of the emulsion. By polyionic it is meant that the blockcomprises ionic (anionic or cationic) repetitive units whatever the pH,or that the block comprises repetitive units that may be neutral orionic (anionic or cationic) depending on the pH of the emulsion (theunits are potentially ionic). A unit that may be neutral or ionic(anionic or cationic), depending on the pH of the composition, will bethereafter referred as an ionic unit (anionic or cationic), or as a unitderiving from an ionic monomer (anionic or cationic), whatever it is ina neutral form or in an ionic form (anionic or cationic).

[0089] Examples of polycationic blocks are blocks comprising unitsderiving from cationic monomers such as:

[0090] aminoalkyl (meth)acrylates, aminoalkyl (meth)acrylamides,

[0091] monomers, including particularly (meth)acrylates, and(meth)acrylamides derivatives, comprising at least one secondary,tertiary or quaternary amine function, or a heterocyclic groupcontaining a nitrogen atom, vinylamine or ethylenimine;

[0092] diallyldialkyl ammonium salts;

[0093] their mixtures, their salts, and macromonomers deriving fromtherefrom.

[0094] Examples of cationic monomers include:

[0095] dimethylaminoethyl (meth)acrylate, dimethylaminopropyl(meth)acrylate, ditertiobutylaminoethyl (meth)acrylate,dimethylaminomethyl (meth)acrylamide, dimethylaminopropyl(meth)acrylamide;

[0096] ethylenimine, vinylamine, 2-vinylpyridine, 4-vinylpyridine;

[0097] trimethylammonium ethyl (meth)acrylate chloride,trimethylammonium ethyl (meth)acrylate methyl sulphate, dimethylammoniumethyl (meth)acrylate benzyl chloride, 4-benzoylbenzyl dimethylammoniumethyl acrylate chloride, trimethyl ammonium ethyl (meth)acrylamido (alsocalled 2-(acryloxy)ethyltrimethylammonium, TMAEAMS) chloride,trimethylammonium ethyl (meth)acrylate (also called2-(acryloxy)ethyltrimethylammonium, TMAEAMS) methyl sulphate, trimethylammonium propyl (meth)acrylamido chloride, vinylbenzyl trimethylammonium chloride,

[0098] diallyldimethyl ammonium chloride,

[0099] monomers having the following formula:

[0100]

[0101] wherein

[0102] R₁ is a hydrogen atom or a methyl or ethyl group;

[0103] R₂, R₃, R₄, R₅ and R₆, which are identical or different, arelinear or branched C₁-C₆, preferably C₁-C₄, alkyl, hydroxyalkyl oraminoalkyl groups;

[0104] m is an integer from 1 to 10, for example 1;

[0105] n is an integer from 1 to 6, preferably 2 to 4;

[0106] Z represents a —C(O)O— or —C(O)NH— group or an oxygen atom;

[0107] A represents a (CH₂)_(p) group, p being an integer from 1 to 6,preferably from 2 to 4;

[0108] B represents a linear or branched C₂-C₁₂, advantageously C₃-C₆,polymethylene chain optionally interrupted by one or more heteroatoms orheterogroups, in particular O or NH, and optionally substituted by oneor more hydroxyl or amino groups, preferably hydroxyl groups;

[0109] X, which are identical or different, represent counterions, and

[0110] their mixtures, and macromonomers deriving therefrom.

[0111] Examples of anionic blocks are blocks comprising units derivingfrom anionic monomers selected from the group consisting of:

[0112] alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monomers comprising a phosphate orphosphonate group,

[0113] alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monocarboxylic acids,

[0114] monoalkylesters of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, dicarboxylic acids,

[0115] monoalkylamides of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, dicarboxylic acids,

[0116] alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, compounds comprising a sulphonicacid group, and salts of alpha-ethylenically-unsaturated compoundscomprising a sulphonic acid group.

[0117] Preferred anionic blocks include blocks comprising deriving fromat least one anionic monomer selected from the group consisting of:

[0118] acrylic acid, methacrylic acid,

[0119] vinyl sulphonic acid, salts of vinyl sulfonic acid,

[0120] vinylbenzene sulphonic acid, salts of vinylbenzene sulphonicacid,

[0121] alpha-acrylamidomethylpropanesulphonic acid, salts ofalpha-acrylamidomethylpropanesulphonic acid

[0122] 2-sulphoethyl methacrylate, salts of 2-sulphoethyl methacrylate,

[0123] acrylamido-2-methylpropanesulphonic acid (AMPS), salts ofacrylamido-2-methylpropanesulphonic acid, and

[0124] styrenesulfonate (SS).

[0125] Examples of neutral blocks (block A or block B) are blockscomprising units deriving from at least one monomer selected from thegroup consisting of:

[0126] acrylamide, methacrylamide,

[0127] amides of alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monocarboxylic acids,

[0128] esters of an alpha-ethylenically-unsaturated, preferablymono-alpha-ethylenically-unsaturated, monocarboxylic acid, for examplealkyl esters such as such as methylacrylate, ethylacrylate,n-propylacrylate, n-butylacrylate, methylmethacrylate,ethylmethacrylate, n-propylmethacrylate, n-butylmethacrylate,2-ethyl-hexyl acrylate, or hydroxyalkyl esters such as2-hydroxyethylacrylate,

[0129] polyethylene and/or polyporpylene oxide (meth)acrylates (i.e.polyethoxylated and/or polypropoxylated (meth)acrylic acid),

[0130] vinyl alcohol,

[0131] vinyl pyrrolidone,

[0132] vinyl acetate, vinyl Versatate,

[0133] vinyl nitriles, preferably comprising from 3 to 12 carbon atoms,

[0134] acrylonitrile,

[0135] vinylamine amides,

[0136] vinyl aromatic compounds, such as styrene, and

[0137] mixtures thereof.

[0138] Block A preferably derives from mono-alpha-ethylenicallyunsaturated monomers. Block B preferably derives frommono-alpha-ethylenically unsaturated monomers. In a preferredembodiment, both block A and block B derive frommono-alpha-ethylenically unsaturated monomers. More precisely, it ismeant that for block A and/or block B, at least 50% of the repeatingunits preferably are mono-alpha-ethylenically-unsaturated monomersderived units.

[0139] The monomers listed above are mono-alpha-unsaturated monomers,except propylene oxide and ethylene oxide.

[0140] In a preferred embodiment, the hydrophobic block (block B)comprises units deriving from butyl-(meth)acrylate, the hydrophilicblock (block A) comprises units deriving from (meth)acrylic-acid, andpolymer H, if comprised in the composition, comprises units derivingfrom (meth)butyl-acrylate. These multiblock copolymers are soluble inethanol and in THF. Solvent B is preferably ethanol or THF. Themultiblock copolymer is preferably a diblock (Block A)-(Block B)copolymer.

[0141] In another preferred embodiment, the hydrophobic block (block B)comprises units deriving from styrene, the hydrophilic block (block A)comprises units deriving from (meth)acrylic-acid, and polymer H, ifcomprised in the composition, comprises units deriving from styrene.These multiblock copolymers are soluble in THF. Solvent B is preferablyTHF. The multiblock copolymer is preferably a diblock (Block A)-(BlockB) copolymer.

[0142] In embodiments wherein the hydrophilic block (block A) comprisesunits deriving from (meth)acrylic-acid block, pH is preferably of lowerthan or equal to 4. At such a low pH the units deriving from(meth)acrylic-acid are usually in an anionic form.

[0143] The weight-average molecular weight of the multiblock copolymeris preferably comprised between 1000 and 100000 g/mol. It is morepreferably comprised between 2000 and 20000 g/mol. Within these ranges,the weight ratio of each block may vary. It is however preferred thateach block have a molecular weight above 500 g/mol, and preferably above1000 g/mol. Within these ranges, the weight ratio between block(s) A andblock(s) B is preferably of at least 50/50.

[0144] Examples of useful multiblock copolymers are copolymers whereinblock B is a hydrophobic block comprising units deriving frombutyl-(meth)acrylate, block A is a hydrophilic block comprising unitsderiving from (meth)acrylic-acid, preferably linear sequenced (blockA)-(block B) diblock copolymers, (block A)-(block B)-(block A) triblockcopolymers, or (block B)-(block A)-(block B) triblock copolymers.Examples include (block A)-(block B) diblock copolymers wherein block Bhas a molecular weight of 3 k, and block A has a molecular weight of 12k (ratio between block(s) A and block(s) B of 80/20). Examples alsoinclude (block A)-(block B) diblock copolymers wherein block B has amolecular weight of 8 k, and block A has a molecular weight of 8 k(ratio between block(s) A and block(s) B of 50/50).

[0145] Examples of useful multiblock copolymers are copolymers whereinblock B is a hydrophobic block comprising units deriving from styrene,block A is a hydrophilic block comprising units deriving from(meth)acrylic-acid, preferably linear sequenced (block A)-(block B)diblock copolymers, (block A)-(block B)-(block A) triblock copolymers,or (block B)-(block A)-(block B) triblock copolymers. Examples include(block A)-(block B) diblock copolymers wherein block B has a molecularweight of 8 k, and block A has a molecular weight of 8 k (ratio betweenblock(s) A and block(s) B of 50/50).

[0146] There are several methods for making block copolymers. Somemethods for making such copolymers are provided below.

[0147] It is possible for example to use anionic polymerization withsequential addition of 2 monomers as described for example by Schmolka,J. Am. Oil Chem. Soc. 1977, 54, 110; or alternatively Wilczek-Veraet etal., Macromolecules 1996, 29, 4036. Another method which can be usedconsists in initiating the polymerization of a block polymer at each ofthe ends of another block polymer as described for example by Katayoseand Kataoka, Proc. Intern. Symp. Control. Rel. Bioact. Materials, 1996,23, 899.

[0148] In the context of the present invention, it is recommended to useliving or controlled polymerization as defined by Quirk and Lee (PolymerInternational 27, 359 (1992)). Indeed, this particular method makes itpossible to prepare polymers with a narrow dispersity and in which thelength and the composition of the blocks are controlled by thestoichiometry and the degree of conversion. In the context of this typeof polymerization, there are more particularly recommended thecopolymers which can be obtained by any so-called living or controlledpolymerization method such as, for example:

[0149] free-radical polymerization controlled by xanthates according tothe teaching of Application WO 98/58974 and U.S. Pat. No. 6,153,705,

[0150] free-radical polymerization controlled by dithioesters accordingto the teaching of Application WO 98/01478,

[0151] free-radical polymerization controlled by dithioesters accordingto the teaching of Application WO 99/35178,

[0152] free-radical polymerization controlled by dithiocarbamatesaccording to the teaching of Application WO 99/35177,

[0153] free-polymerization using nitroxide precursors according to theteaching of Application WO 99/03894,

[0154] free-radical polymerization controlled by dithiocarbamatesaccording to the teaching of Application WO 99/31144,

[0155] free-radical polymerization controlled by dithiocarbazatesaccording to the teaching of Application WO 02/26836,

[0156] free-radical polymerization controlled by halogenated Xanthatesaccording to the teaching of Application WO 00/75207 and U.S.application Ser. No. 09/980,387,

[0157] free-radical polymerization controlled by dithiophosphoroestersaccording to the teaching of Application WO 02/10223,

[0158] free-radical polymerization controlled by a transfer agent in thepresence of a disulphur compound according to the teaching ofApplication WO 02/22688,

[0159] atom transfer radical polymerization (ATRP) according to theteaching of Application WO 96/30421,

[0160] free-radical polymerization controlled by iniferters according tothe teaching of Otu et al., Makromol. Chem. Rapid. Commun., 3, 127(1982),

[0161] free-radical polymerization controlled by degenerative transferof iodine according to the teaching of Tatemoto et al., Jap. 50, 127,991 (1975), Daikin Kogyo Co Ltd Japan, and Matyjaszewski et al.,Macromolecules, 28, 2093 (1995),

[0162] group transfer polymerization according to the teaching ofWebster O. W., “Group Transfer Polymerization”, p. 580-588, in the“Encyclopedia of Polymer Science and Engineering”, Vol. 7, edited by H.F. Mark, N. M. Bikales, C. G. Overberger and G. Menges, WileyInterscience, New York, 1987,

[0163] radical polymerization controlled by tetraphenylethanederivatives (D. Braun et al., Macromol. Symp., 111, 63 (1996)),

[0164] radical polymerization controlled by organocobalt complexes(Wayland et al., J. Am. Chem. Soc., 116, 7973 (1994)).

[0165] Preferred processes are sequenced living free-radicalpolymerization processes, involving the use of a transfer agent.Preferred transfer agents are agents comprising a group of formula—S—C(S)—Y—, —S—C(S)—S—, or —S—P(S)—Y—, or —S—P(S)—S—, wherein Y is anatom different from sulfur, such as an oxygen atom, a nitrogen atom, anda carbon atom. They include dithioester groups, thioether-thione groups,dithiocarbamate groups, dithiphosphoroesters, dithiocarbazates, andxanthate groups. Examples of groups comprised in preferred transferagents include groups of formula —S—C(S)—NR—NR′₂, —S—C(S)—NR—N═CR′₂,—S—C(S)—O—R, —S—C(S)—CR═CR′₂, and —S—C(S)—X, wherein R and R′ are oridentical or different hydrogen atoms, or organic groups such ashydrocarbyl groups, optionally substituted, optionally comprisingheteroatoms, and X is an halogen atom. A preferred polymerizationprocess is a living radical polymerization using xanthates.

[0166] Copolymers obtained by a living or controlled free-radicalpolymerization process may comprise at least one transfer agent group atan end of the polymer chain. In particular embodiment such a group isremoved or deactivated.

[0167] For example, a “living” or “controlled” radical polymerizationprocess used to make the di-block copolymers comprises the steps of:

[0168] a) reacting a mono-alpha-ethylenically-unsaturated monomer, atleast a free radicals source compound, and a transfer agent, to obtain afirst block, the transfer agent being bounded to said first block,

[0169] b) reacting the first block, anothermono-alpha-ethylenically-unsaturated monomer, and, optionally, at leasta radical source compound, to obtain a di-block copolymer, and then

[0170] c) optionally, reacting the transfer agent with means to renderit inactive.

[0171] During step a), a first block of the polymer is synthesized.During step b), b1), or b2), another block of the polymer issynthesized.

[0172] Examples of transfer agents are transfer agents of the followingformula (I):

[0173] wherein:

[0174] R represents an R²O—, R²R′²N— or R³— group, R² and R′², which areidentical or different, representing (i) an alkyl, acyl, aryl, alkene oralkyne group or (ii) an optionally aromatic, saturated or unsaturatedcarbonaceous ring or (iii) a saturated or unsaturated heterocycle, itbeing possible for these groups and rings (i), (ii) and (iii) to besubstituted, R³ representing H, Cl, an alkyl, aryl, alkene or alkynegroup, an optionally substituted, saturated or unsaturated(hetero)cycle, an alkylthio, alkoxycarbonyl, aryloxycarbonyl, carboxyl,acyloxy, carbamoyl, cyano, dialkyl- or diarylphosphonato, or dialkyl- ordiarylphosphinato group, or a polymer chain,

[0175] R¹ represents (i) an optionally substituted alkyl, acyl, aryl,alkene or alkyne group or (ii) a carbonaceous ring which is saturated orunsaturated and which is optionally substituted or aromatic or (iii) anoptionally substituted, saturated or unsaturated heterocycle or apolymer chain, and

[0176] The R¹, R², R′² and R³ groups can be substituted by substitutedphenyl or alkyl groups, substituted aromatic groups or the followinggroups: oxo, alkoxycarbonyl or aryloxycarbonyl (—COOR), carboxyl(—COOH), acyloxy (—O₂CR), carbamoyl (—CONR₂), cyano (—CN),alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkylcarbonyl,isocyanato, phthalimido, maleimido, succinimido, amidino, guanidino,hydroxyl (—OH), amino (—NR₂), halogen, allyl, epoxy, alkoxy (—OR),S-alkyl, S-aryl or silyl, groups exhibiting a hydrophilic or ionicnature, such as alkaline salts of carboxylic acids or alkaline salts ofsulphonic acid, poly(alkylene oxide) (PEO, PPO) chains, or cationicsubstituents (quaternary ammonium salts), R representing an alkyl oraryl group.

[0177] Preferably, the transfer agent of formula (I) is adithiocarbonate chosen from the compounds of following formulae (IA),(IB) and (IC):

[0178] wherein:

[0179] R² and R²′ represent (i) an alkyl, acyl, aryl, alkene or alkynegroup or (ii) an optionally aromatic, saturated or unsaturatedcarbonaceous ring or (iii) a saturated or unsaturated heterocycle, itbeing possible for these groups and rings (i), (ii) and (iii) to besubstituted,

[0180] R¹ and R¹′ represent (i) an optionally substituted alkyl, acyl,aryl, alkene or alkyne group or (ii) a carbonaceous ring which issaturated or unsaturated and which is optionally substituted or aromaticor (iii) an optionally substituted, saturated or unsaturated heterocycleor a polymer chain, and

[0181] p is between 2 and 10.

[0182] Other examples of transfer agents are transfer agents of thefollowing formulae (II) and (III):

[0183] wherein

[0184] R¹ is an organic group, for example a group R¹ as defined abovefor tranfer agents of formulae (I), (IA), (IB), and (IC),

[0185] R², R³, R⁴, R⁷, and R⁸ which are identical or different arehydrogen atoms or organic groups, optionally forming rings. Examples ofR², R³, R⁴, R⁷, and R⁸ organic groups include hydrocarbyls, subsitutedhydrocabyls, heteroatom-containing hydrocarbyls, and substututedheteroatom-containing hydrocarbyls.

[0186] The mono-alpha-ethylenically-unsaturated monomers and theirproportions are chosen in order to obtain the desire properties for theblock(s). According to this process, if all the successivepolymerizations are carried out in the same reactor, it is generallypreferable for all the monomers used during one stage to have beenconsumed before the polymerization of the following stage begins,therefore before the new monomers are introduced. However, it may happenthat monomers of the preceding stage are still present in the reactorduring the polymerization of the following block. In this case, thesemonomers generally do not represent more than 5 mol % of all themonomers.

[0187] The polymerization can be carried out in an aqueous and/ororganic solvent medium. The polymerization can also be carried out in asubstantially neat melted form (bulk polymerization), or according to alatex type process in an aqueous medium.

[0188] Polymer H

[0189] Polymer H is preferably a hydrophobic polymer. Hydrophobic isunderstood as defined above. The capsules obtained from the compositionshaving polymer H usually have interesting properties, including higherencapsulation rates, or a strengthen shell. Having such a strengthenedshell allows easier formulation by preventing destruction whenprocessing, or allows controlled release (long lasting). Hydrophobicpolymers include polymers comprising repeating units deriving frommonomers listed above for block B.

[0190] In a preferred embodiment block B and polymer H are the same. Itmeans that they comprise units deriving from the same monomers. Thus, inan preferred embodiment the hydrophilic block (block B) and polymer Hare polybutylacrylate, polybutylmethacrylate or styrene. They may havethe same or different molecular weights. According to this preferredembodiment, the polymer H has a weight-average molecular weight ofbetween 500 g/mol and 15000 g/mol.

[0191] In a particular embodiment, polymer H has a glass transitiontemperature of greater than 50° C., preferably of greater than 100° C.Polystyrene is an example. Capsules obtained form compositionscomprising such a polymer H present a shell with interesting mechanicalproperties. It makes it possible to make empty capsules forreinforcement of materials, for example for making light materials. Itallows also making pigment or ink capsules.

[0192] For a given amount of polymer H is the composition, the moremultiblock copolymer is comprised in the composition (in the droplets),the smaller the size of the droplets is. Controlling the size of thedroplets, allows controlling the size of the capsules made therefrom,and thus may allows controlling efficiency of encapsulation of anactive.

[0193] Actives

[0194] The composition according to the invention, and the capsulesderiving therefrom may comprise an additive being an active ingredientto be protected, vectorized or released with control, a reactivecompound to be transformed by a chemical reaction, or a compound to beremoved from a liquid phase.

[0195] Reactive compounds are for example compounds to be polymerized inthe droplets of the composition. Compounds to be removed are for examplecompounds soluble in solvent B, to be remove from solvent A by aliquid-liquid separation process.

[0196] The capsules may be comprised in a composition that may beintroduced in an animal or human body, applied onto a surface such asskin, hair, a fabric, a hard surface, or spread in a field. Activeingredients are compounds comprised in the composition to be delivered,quickly or slowly, suddenly, for example by breaking the shell, orprogressively for example by diffusing through the shell, in thedestination environment. Thus, the capsules may comprise actives usefulin cosmetic compositions, drug compositions, perfumes, agrochemicalcompositions.

[0197] Active ingredients that may be comprised in the compositionand/or in the capsules deriving therefrom, include organic and inorganiccompounds. Inorganic compounds are for example inorganic particles, suchas nanoparticles, said particles having optionally a surface treatmentfor controlling their compatibility and/or dispersion, in solvent Band/or in polymer H.

[0198] The actives ingredients may be hydrophobic compounds, or may becomprised in a hydrophobic compound, for example comprised in polymer H.

[0199] Examples of actives being the hydrophobic compound, or beingcomprising therein, that may be used in food industry include activesused in food industry include mono-, di- and triglycerides, essentialoils, aromas, and food compatible coloring agents.

[0200] Examples of actives being the hydrophobic compound, or beingcomprising therein, that may be used in cosmetics include fragrances,perfumes, silicone oils, such as dimethicones, lipophilic vitamins suchas A vitamin.

[0201] Examples of actives being the hydrophobic compound, or beingcomprising therein, that may be used in paints, include alkydes resins,epoxy resins, (poly)isocyanates masked or not masked.

[0202] Examples of actives being the hydrophobic compound, or beingcomprising therein, that may be used in paper industry includealkylcetene dimer (AKD), and alkenyl succinic anhydride (ASA).

[0203] Examples of actives being the hydrophobic compound, or beingcomprising therein, that may be used in agrochemicals includeα-cyano-phenoxybenzyl carboxylates,α-cyano-halogénophénoxy-carboxylates, N-méthylcarbonates comprisongaromatic groups, Aldrin, Azinphos-methyl, Benfluralin, Bifenthrin,Chlorphoxim, Chlorpyrifos, Fluchloralin, Fluroxypyr, Dichlorvos,Malathion, Molinate, Parathion, Permethrin, Profenofos, Propiconazole,Prothiofos, Pyrifenox, Butachlor, Metolachlor, Chlorimephos, Diazinon,Fluazifop-P-butyl, Heptopargil, Mecarbam, Propargite, Prosulfocarb,Bromophos-ethyl, Carbophenothion, and Cyhalothrin.

[0204] Examples of actives being the hydrophobic compound, or beingcomprising therein, that may be used in detergency compositions includesilicone antifoaming agents, fragrances and perfumes biocide agents,fragrances and perfumes.

[0205] Examples of actives being the hydrophobic compound, or beingcomprising therein, also include organic solvents or mixtures thereof,such as solvent used for cleaning or stripping such as aromatic oilcuts, terpenic compounds such as D- or L-limonenes, and solvents such asSolvesso®. Solvents also include aliphatic esters such as methyl estersof a mixture of acetic acid, succinic acid, glutaric acid (mixture ofNylon monomer preparation by-products), and chlorinated solvents.

[0206] The actives ingredients may be hydrophilic compounds, miscible ordispersible in solvent A and optionally B, comprised in the capsules,and optionally also out of the capsules.

[0207] Examples of actives include hydrophilic actives that may beintroduced in a classical vesicle, known by the one skilled in the art.

[0208] Examples of actives include hydrophilic actives that may be usedin cosmetics, including compounds having a cosmetic effect, atherapeutic effect, and compounds used for treating hair or skin.

[0209] Thus, active compounds that may be used include hair and skinconditioning agents, such as polymers comprising quaternary ammoniumgroups, optionally comprised in heterocycles (quaternium orpolyquaternium type compounds), moisturizing agents, fixing (styling)agents, more preferably fixing polymers such as homo-, co-, orter-polymers, for example acrylamide, acrylamide/sodium acrylate,sulfonated polystyrene, cationic polymers, polyvinylpyrrolidone,polyvinyl acetate.

[0210] Examples of hydrophilic actives include coloring agents,astringents, that may be used in deodorizing compositions, such asaluminum salts, zirconium salts, antibacterial agents, anti-inflammatoryagents, anesthetizing agents, solar filter agents.

[0211] Examples of actives include hydrophilic actives that may be usedin cosmetics, for example α- and β-hydroxyacids, such as citric-acid,lactic acid, glycolic acid, salicylic acid, cicarboxylic acids,preferably unsaturated ones comprising from 9 to 16 carbon atoms, suchas azelaic acid, C vitamin and drivatives thereof, particularlyphophate-based or glycosyl-based derivatives, biocidal agents, such aspreferably cationic ones (for example Glokill PQ, Rhodoaquat RP50,marketed by Rhodia).

[0212] Examples of actives include hydrophilic actives that may be usedin food industry, for example divalent calcium salts (phosphates,chlorides . . . ), that may be used for cross-linking texturing polymerssuch as alginates, carraghenans. Sodium bicarbonate may also be used.

[0213] Examples of actives include hydrophilic actives that may be usedin agrochemicals, including hydrophilic pesticides and pesticideshydrophilic nutritive ingredients.

[0214] Examples of actives include hydrophilic actives that may be usedin oil fields, including hydrophilic compounds useful for cementing,drilling, or stimulating oil wells (for example par fracturing).Examples include cross-linking catalysts such as lithium salts,chlorides, acetate. Examples also include compounds that degradepolysaccharides, such as carboxylic acids (for example citric acid),enzymes, and oxidizing agents.

[0215] Examples of actives include actives that may be used in paperindustry, including calcium chloride, and hydrochloric acid.

[0216] Examples of actives also include bleaches, to be protected fromoxidation by agents in laundry detergent formulations, enzymes,phosphate salts and cationic compounds having a biocide action.

[0217] Examples of actives include also cationic surfactants used forfabric care. Capsules make it possible to avoid contact of suchsurfactants with anionic surfactants usually comprised in laundrydetergent formulation, and makes it possible to make two in oneformulations having a detergent action and a fabric care action.

[0218] Examples of useful actives also include biocides such as:

[0219] Tolcide (Tetrakishydroxymethylphosphonium sulfate, THPS),

[0220] benzyldimethyldodecylammonium chloride (BDAC),

[0221] cetrimonim bromide (CTAB), for example a compound marketed asRhodaquat M-242.

[0222] Examples of useful actives also include enzymes such as serineclass proteases, for example elastase.

[0223] Composition

[0224] In an advantageous composition solvent A is water, block Acomprises hydrophilic units, block B comprises hydrophobic units, theweight ratio between the amount of hydrophobic units and the hydrophilicunits is of lower than or equal to 50/50, and the amount by weight ofmultiblock copolymer in the composition is of at least 0,005 %, and ofless than 20%.

[0225] When comprising polymer H, the above advantageous composition,the weight ratio between the amount of hydrophobic units and thehydrophilic units is lower than or equal to 50/50, polymer H compriseshydrophobic units, said units being the same than the units comprised inblock B, and the amount by weight of polymer H in the composition is ofat least 1%, the amount by weight of the multiblock copolymer togetherwith polymer H, in the composition, being preferably of less than 20%.

[0226] In a particular embodiment, the hydrophobic block comprises unitsderiving from butyl-(meth)acrylate, the hydrophilic block comprisesunits deriving from (meth)acrylic-acid, and polymer H, if comprised inthe composition, comprises units deriving from butyl-(meth)acrylate.Solvent B is then preferably THF or ethanol. If solvent B is ethanol,the ratio by weight (amount of solvent B)/(amount of solvent B+amount ofwater) in the composition is preferably comprised between 0.7 and 0.8.If solvent B is THF, the ratio by weight (amount of solvent B)/(amountof solvent B+amount of water) in the composition is preferably comprisedbetween 0.3 and 0.7, preferably between 0.4 and 0.7.

[0227] In another particular embodiment, the hydrophobic block comprisesunits deriving from styrene, the hydrophilic block comprises unitsderiving from (meth)acrylic-acid, and polymer H, if comprised in thecomposition, comprises units deriving from styrene solvent B is thenpreferably THF. If solvent B is THF, the ratio by weight (amount ofsolvent B)/(amount of solvent B+amount of water) in the composition ispreferably comprised between 0.7 and 0.9.

[0228] Process for Making the Composition and/or the Capsules

[0229] The composition according to the invention may be prepared bymixing solvent A, solvent B, the multiblock copolymer, and theadditional compound. Mixing may be carried out in any order and may becarried out with using premixes. A useful premix is a solution premixcomprising solvent B, the multiblock copolymer and optionally polymer H.

[0230] Thus, a composition according to the invention comprising atleast two miscible solvents wherein solvent A is water, can be preparedby mixing:

[0231] water,

[0232] solvent B,

[0233] a multiblock copolymer comprising at least two blocks, block Aand block B, wherein:

[0234] block A is hydrophilic, soluble in water and in solvent B,

[0235] block B is hydrophobic, soluble in solvent B, and

[0236] block B is not soluble in water, and

[0237] at least one additional compound being:

[0238] a linear polymer H, soluble in solvent B, and not soluble insolvent A, and/or

[0239] an additive being an active ingredient to be protected,vectorized or released with control, a reactive compound to betransformed by a chemical reaction, or a compound to be removed from aliquid phase.

[0240] More preferably, the composition can be prepared by mixing

[0241] water

[0242] optionally, at least one additive being an active ingredient tobe protected, vectorized or released with control, a reactive compoundto be transformed by a chemical reaction, or a compound to be removedfrom a liquid phase, said additive being optionally dispersed ordissolved in water, and

[0243] a solution comprising:

[0244] solvent B,

[0245] a multiblock copolymer comprising at least two blocks, block Aand block B, wherein:

[0246] block A is hydrophilic, soluble in water and in solvent B,

[0247] block B is hydrophobic, soluble in solvent B, and

[0248] block B is not soluble in water, and

[0249] optionally, a linear polymer H, soluble in solvent B, and notsoluble in solvent A,

[0250] provided that the obtained composition comprises polymer H and/orthe additive.

[0251] If solvent B is ethanol, and the multiblock copolymer has ahydrophobic block comprising units deriving from butyl-(meth)acrylate,and a hydrophilic block comprising units deriving from(meth)acrylic-acid, it is preferred that from 0.2 to 0.3 parts by weightof water be mixed for 1 part by weight of water together with solvent B.

[0252] If solvent B is THF, and the multiblock copolymer has ahydrophobic block comprising units deriving from butyl-(meth)acrylate,and a hydrophilic block comprising units deriving from(meth)acrylic-acid, it is preferred that from 0.3 to 0.7, preferably 0.3to 0.6, parts by weight of water be mixed for 1 part by weight of watertogether with solvent B.

[0253] If solvent B is THF, and the multiblock copolymer has ahydrophobic block comprising units deriving from styrene, it ispreferred that from 0.1 to 0.3, preferably 0.3 to 0.6, parts by weightof water be mixed for 1 part by weight of water together with solvent B.

[0254] In a particular embodiment solvent A is water, and is added,optionally with additives dispersed or dissolved therein, to a solutionpremix comprising solvent B, the multiblock copolymer, and optionallypolymer H.

[0255] Different solvents, and multiblock copolymer, and differentamounts thereof, may be used, to prepare a useful composition accordingto the invention, and to prepare then capsules, as long as a phaseseparation occurs. Some preferred systems have been described above forwater/ethanol and water/THF systems, but the invention is not limited tothem.

[0256] Indeed, a very practical starting product, useful for preparingdispersions, capsules, vesicles, or the like, is a solution, comprising:

[0257] a water-miscible solvent B,

[0258] a multiblock copolymer comprising at least two blocks, block Aand block B, wherein:

[0259] block A is hydrophilic, soluble in water and in thewater-miscible solvent,

[0260] block B is hydrophobic, soluble in the water-miscible solvent,and

[0261] block B is not soluble in water,

[0262] a linear polymer H, soluble in the water-miscible solvent, andnot soluble water, and

[0263] optionally, an active ingredient, a reactive compound to betransformed by a chemical reaction, or a compound to be removed from aliquid phase, said ingredient or compound being soluble or dispersiblein solvent B,

[0264] wherein block B and polymer H comprise repetitive units, saidrepetitive units being the same.

[0265] In a particular embodiment of the solution, solvent B is ethanolor THF, block B is a hydrophobic block comprising units deriving frombutyl-(meth)acrylate, block A is a hydrophilic block comprising unitsderiving from (meth)acrylic-acid, and polymer H comprises units derivingfrom butyl-(meth)acrylate. The block copolymer is preferably a linearsequenced (block A)-(block B) diblock copolymer, (block A)-(blockB)-(block A) triblock copolymer, or (block B)-(block A)-(block B)triblock copolymer.

[0266] In another particular embodiment of the solution, solvent B isTHF, block B is a hydrophobic block comprising units deriving fromstyrene, block A is a hydrophilic block comprising units deriving from(meth)acrylic-acid, and polymer H comprises units deriving frombutyl-(meth)acrylate. The block copolymer is preferably a linearsequenced (block A)-(block B) diblock copolymer, (block A)-(blockB)-(block A) triblock copolymer, or (block B)-(block A)-(block B)triblock copolymer.

[0267] When block A is a block comprising units deriving from(meth)acrylic-acid, it is preferred that the pH be of lower than orequal to 4 when adding water.

[0268] According to an interesting aspect of the invention, thecomposition is quenched in order to obtain capsules, dispersed insolvent A. The capsules obtained by quenching the composition comprise ashell, either empty or comprising inside at least one internal phaseand/or additive. Quenching is performed by removing or partiallyremoving solvent B from the droplets comprised in the composition,comprising at least the miscible solvents, water and solvent B. Thecapsules obtained are dispersed in solvent A, which is preferably water.

[0269] Advantageously, solvent A is water, and removing or partiallyremoving (quenching) is carried out by dilution with water, dialysis, orevaporation, optionally under vacuum, optionally with heating.

[0270] In a particular embodiment solvent A is water, the droplets inthe composition comprise the additive (such as an active), and thecapsules obtained by quenching comprise inside at least the additive.

[0271] In another particular embodiment, the droplets of the compositioncomprise at least two miscible solvents and comprise a polymer H, havinga glass transition temperature of greater than 50° C., preferably ofgreater than 100° C. The capsules obtained have then the shellcomprising polymer H. The shell of the capsules then have a shell withinteresting properties, as mentioned above. According to thisembodiment, it is possible to make empty capsules for reinforcement ofmaterials, for example for making light materials. It allows also makingpigment or ink capsules.

[0272] After quenching (removal or partially removal of solvent B),solvent A, for example water, may be removed or partially removed, toobtained dry capsules, substantially dry capsules, or a concentrateddispersions of capsules. Said dry capsules, substantially dry capsules,or a concentrated dispersions of capsules can be re-dispersed in aliquid medium, for example solvent A, preferably water, or re-diluted.They may also be compounded in solid materials.

[0273] The capsules might be used in formulations or environments havingdifferent pH. For example home-care detergents formulations, or waterhaving the detergent formulation, are usually rather basic. When block Ais sensible to pH, as a block comprising units deriving from(meth)acrylic acid usually is, the stability of the capsules obtainedafter quenching, and the encapsulation rate of actives, can be improvedat higher pH, by adding to the dispersion comprising the capsules(dispersion in solvent A) a polymer having cationic units. The polymermight be for example a diblock copolymer comprising an hydrophiliccationic block and an hydrophilic neutral block. Good results can beobtained by using a diblock copolymer having a polyTMAEAMS block and apolyacrylamide block. Good results can also be obtained by using adiblock copolymer having a poly(chloride 2-vinylpyridine) block and apolyethylene oxide block. Using the polymer having cationic units alsoallows having actives that are pH-sensible. It is thus possible theprotect an active that is pH-sensible (incompatibility and/ordegradation at pH of higher than 4), in the capsules, from asubstantially high pH environment.

[0274] The process for preparing the capsules may comprise optionalsteps. The composition, before quenching, can be heat-treated, forexample at temperatures of from 40 to 90° C. Such a heat treatment helpsin improving the encapsulation rate of actives. The composition can beextruded, before quenching, through a membrane comprising pores, forexample de polycarbonate or a PVDF membrane comprising pores. Such anextrusion step is known by the one skilled in the art of vesicles, forexample in pharmaceutical industry for preparation of monodispersedphospholipid-based vesicles. This allows obtaining smaller capsules witha narrower size dispersion. It can also somehow allow strengthening thevesicle membrane. This allows also improving the stability (decreasingaggregation problems for example) of the dispersion comprising thecapsules obtained after quenching.

[0275] When preparing capsules having an active, the dispersioncomprising the capsules, obtained after quenching, can be dialyzed,according to conventional techniques, in order to withdraw actives thathave not been encapsulated and/or remaining solvent B.

[0276] Some illustrative but non-limiting examples are providedhereunder for the better understanding of the invention.

EXAMPLES

[0277] Compounds used:

[0278] Diblock copolymer: a polybutylacrylate—polyacrylic acid(PBA-b-PAA) block copolymer, having a weight-average molecular weight of15,000 g/mol, comprising 50 wt % of the polybutylacrylate block and 50wt % of the polyacrylic acid block. Solid Form.

[0279] Dye: 10⁻⁵ M Alexa Fluor®594 in water Mw 759, Molecular Probes.

[0280] Polymer H: a polybutylacrylate homopolymer having aweight-average molecular weight of 1000 g/mol.

[0281] CTAB: cetrimonim bromide, marketed as Rhodaquat M-242.

[0282] cationic block copolymer: diblock copolymer having a 11 kpolyTMAEAMS block and a 30 k polyacrylamide block.

Example 1

[0283] Dye Encapsulation with a Diblock Copolymer

[0284] 0.45 g 8 k-8 k diblock polymer solids, and 1.05 g 75/25 by wt ofa solution ethanol/aqueous dye, are mixed vigorously together. Themixture is then heated at 86° C. At that temperature, a clarification ofthe mixture occurs. A composition comprising two phases is obtained. Itcomprises about 20% by weight of copolymer. The composition is thenextruded through a filter PVDF 0.2 μm filter. The extruded product isthen quenched by dilution by 3 folds its original concentration.Capsules comprising the dye are formed. They are dispersed in a liquidbeing substantially water, and comprising untrapped dye. The capsulesdispersion comprises about 6.7% of diblock copolymer. The untrapped isremoved dye by dialyzing through a membrane (MWCO 3 k, regeneratedcellulose Slide-a-Lyser dialysis cassette, Pierce), at about pH 2-3against ˜10% ethanol.

[0285] Fluorescence measurement is performed using an Hitachi F4500apparatus, at □excitation=595 nm and □emission=612 nm.

[0286] The fluorescence measurement shows that the amount of dyeremaining is ca. 30% compared to without dialysis.

Example 2

[0287] Dye Encapsulation with a Diblock Copolymer and Polymer H

[0288] The same procedure than in Example 1 is carried out, with using:

[0289] 0.15 g 8 k-8 k diblock copolymer solids

[0290] 0.075 g 1 k polymer H

[0291] 1.275 g 75/25 by wt ethanol/aqueous dye.

[0292] Before quenching the amount of polymer if about 10%. Afterquenching the amount of polymer is of about 3.3%.

[0293] The fluorescence measurement shows that the amount of dyeremaining is ca. 7% compared to without dialysis.

Example 3

[0294] CTAB Encapsulation with Diblock at pH 2

[0295] A mixture of a solution of 25 wt % CTAB in water, a solution of40 wt % diblock copolymer ethanol, more ethanol to reach a concentrationof CTAB of 6.25 wt %, a concentration of diblock copolymer of 10 wt %,and a ratio ethanol/(ethanol+water) Φ_(EtOH) of 0.75, is prepared. Themixture is then heated to 66° C. and then cool with mixing. Acomposition comprising two phases is obtained. The composition is thenextruded through a filter PVDF 0.2 μm filter. The extruded product isthen quenched by dilution by 3 folds its original concentration.Capsules comprising CTAB are formed. They are dispersed in a liquidbeing substantially water. The dispersion of capsules is then dialyzedas in example 1.

[0296] The encapsulation rate of CTAB is of 80%. This amount of trappedCTAB is based on ¹H-NMR integrations on methyl protons next to thenitrogen.

Example 4

[0297] CTAB Encapsulation with Diblock at pH 8-9

[0298] A mixture of a solution of 10 wt % CTAB in water with dye(10⁻⁵M), a solution of 40 wt % diblock copolymer ethanol, more ethanoland water, is prepared to reach a concentration of CTAB of 6.25 wt %, aconcentration of diblock copolymer of 10 wt %, and a ratioethanol/(ethanol+water) Φ_(EtOH) of 0.75, is prepared. The mixture isthen heated to 66° C. and then cool with mixing. A compositioncomprising two phases is obtained. The extruded product is then quenchedby dilution by 5 folds its original concentration. Capsules comprisingCTAB are formed. They are dispersed in a liquid being substantiallywater. 0.03% by weight of the cationic diblock copolymer is added. ThepH is raised to 8-9. The dispersion of capsules is then dialyzed as inexample 1.

[0299] The fluorescence measurement shows that the amount of dyeremaining is ca. 35% compared to without dialysis.

1. A composition comprising at least two miscible solvents, solvent Aand solvent B, wherein the composition comprises liquid droplets of aninternal phase dispersed in an external liquid phase, the droplets ofthe internal phase comprising: solvent B, a multiblock copolymercomprising at least two blocks, block A and block B, wherein: block A issoluble in solvent A and in solvent B, block B is soluble in solvent B,and block B is not soluble in solvent A, optionally, solvent A, and atleast one additional compound being: a linear polymer H, soluble insolvent B, and not soluble in solvent A, and/or an additive being anactive ingredient to be protected, vectorized or released with control,a reactive compound to be transformed by a chemical reaction, or acompound to be removed from a liquid phase, the external liquid phasecomprising solvent A, optionally solvent B, and optionally an additiveas mentioned above, provided that the weight ratio (solvent B)/(solventA+solvent B) in the droplets of the internal phase is greater than theweight ratio (solvent B)/(solvent A+solvent B) in the external phase. 2.The composition according to claim 1, wherein the multiblock copolymeris: a star-shaped copolymer, a grafted copolymer, or a linear sequencedblock copolymer.
 3. The composition according to claim 2, wherein themultiblock copolymer is a linear sequenced (block A)-(block B) diblockcopolymer, (block A)-(block B)-(block A) triblock copolymer, or (blockB)-(block A)-(block B) triblock copolymer.
 4. The composition accordingto one of claims 1 to 3, comprising the linear copolymer H, whereinblock B and polymer H comprise repetitive units, said repetitive unitsof block B and polymer H being the same.
 5. The composition according toone of claims 1 to 4, wherein the weight ratio between block(s) A andblock(s) B is of at least 50/50.
 6. The composition according to one ofclaims 1 to 5, wherein solvent A is water, block A is hydrophilic, andblock B is hydrophobic.
 7. The composition according to claim 6,wherein: solvent B is ethanol and the external phase comprises a mixtureof ethanol and water, or solvent B is tetrahydrofuran (THF) and theexternal phase comprises a mixture of tetrahydrofuran (THF) and water.8. The composition according to one of claims 6 to 7, wherein, block Acomprises hydrophilic units, block B comprises hydrophobic units, andthe weight ratio between the amount of hydrophobic units and thehydrophilic units is of lower than or equal to 50/50.
 9. The compositionaccording to one of claims 6 to 8, wherein: block A compriseshydrophilic units, block B comprises hydrophobic units, and the weightratio between the amount of hydrophobic units and the hydrophilic unitsis of lower than or equal to 50/50, the amount by weight of multiblockcopolymer in the composition is of at least 0,005%, and of less than20%.
 10. The composition according to claim 9, comprising polymer H,wherein: block A comprises hydrophilic units, block B compriseshydrophobic units, and the weight ratio between the amount ofhydrophobic units and the hydrophilic units is of lower than or equal to50/50, polymer H comprises hydrophobic units, said units being the samethan the units comprised in block B, and the amount by weight of polymerH in the composition is of at least 1%, the amount by weight of themultiblock copolymer together with polymer H, in the composition, beingpreferably of less than 20%.
 11. The composition according to one ofclaims 6 to 10, wherein the hydrophobic block comprises units derivingfrom butyl-(meth)acrylate, the hydrophilic block comprises unitsderiving from (meth)acrylic-acid, and polymer H, if comprised in thecomposition, comprises units deriving from butyl-(meth)acrylate.
 12. Thecomposition according to claim 11, wherein solvent B is THF or ethanol.13. The composition according to one of claims 6 to 10, wherein thehydrophobic block comprises units deriving from styrene, the hydrophilicblock comprises units deriving from (meth)acrylic-acid, and polymer H,if comprised in the composition, comprises units deriving from styrene.14. The composition according to claim 13, wherein solvent B is THF. 15.The composition according to claims 11 or 12, wherein solvent B isethanol and the ratio by weight (amount of solvent B)/(amount of solventB+amount of water) in the composition is comprised between 0.7 and 0.8.16. The composition according to claims 11 or 12, wherein solvent B isTHF and the ratio by weight (amount of solvent B)/(amount of solventB+amount of water) in the composition is comprised between 0.3 and 0.7,preferably between 0.4 and 0.7.
 17. The composition according to claim13 or 14, wherein solvent B is THF, and the ratio by weight (amount ofsolvent B)/(amount of solvent B+amount of water) in the composition iscomprised between 0.7 and 0.9.
 18. The composition according to one ofclaims 1 to 14, comprising polymer H, wherein polymer H has a glasstransition temperature of greater than 50° C., preferably of greaterthan 100° C.
 19. The composition according to one of claims 6 to 18,wherein block A comprises units deriving form (meth)acrylic-acid block,and pH is of lower than or equal to
 4. 20. A process for preparingcapsules comprising a shell, either empty or comprising inside at leastone internal phase and/or additive, comprising the step of: removing orpartially removing solvent B from droplets comprised in a compositioncomprising at least two miscible solvents, solvent A and solvent B, asdefined in one of claims 1 to 19, to obtain capsules dispersed insolvent A.
 21. The process according to claim 20, wherein solvent A iswater, and wherein removing or partially removing is carried out bydilution with water, dialysis, or evaporation, optionally under vacuum,optionally with heating.
 22. The process according to claims 20 or 21wherein: solvent A is water the droplets in the composition comprisingat least two miscible solvents comprise the additive, and the capsulescomprise inside at least the additive.
 23. The process according toclaims 20 or 21 wherein: the droplets in the composition comprising atleast two miscible solvents comprise polymer H, and polymer H has aglass transition temperature of greater than 50° C., preferably ofgreater than 100° C., and the shell comprise polymer H.
 24. The processaccording to one of claims 20 to 23, wherein solvent A is also removedor partially removed, after removal or partially removal of solvent B,to obtained dry capsules, substantially dry capsules, or a concentrateddispersion of capsules.
 25. The process according to claim 24, whereindry capsules or substantially dry capsules, are re-dispersed in solventA.
 26. The process according to one of claims 20 to 23, wherein thecomposition comprising at least two miscible solvents is a compositionas defined in one of claims 6 to 19, wherein solvent A is water, and isprepared by mixing: water, solvent B, a multiblock copolymer comprisingat least two blocks, block A and block B, wherein: block A ishydrophilic, soluble in water and in solvent B, block B is hydrophobic,soluble in solvent B, and block B is not soluble in water, and at leastone additional compound being: a linear polymer H, soluble in solvent B,and not soluble in solvent A, and/or an additive being an activeingredient to be protected, vectorized or released with control, areactive compound to be transformed by a chemical reaction, or acompound to be removed from a liquid phase.
 27. The process according toclaim 26, wherein the composition comprising at least two misciblesolvents, water and solvent B, is prepared by mixing water optionally,at least one additive being an active ingredient to be protected,vectorized or released with control, a reactive compound to betransformed by a chemical reaction, or a compound to be removed from aliquid phase, said additive being optionally dispersed or dissolved inwater, and a solution comprising: solvent B, a multiblock copolymercomprising at least two blocks, block A and block B, wherein: block A ishydrophilic, soluble in water and in solvent B, block B is hydrophobic,soluble in solvent B, and block B is not soluble in water, andoptionally, a linear polymer H, soluble in solvent B, and not soluble insolvent A, provided that the obtained composition comprises polymer Hand/or the additive.
 28. The process according to claim 26 or 27,wherein the solvent B is ethanol, the multiblock copolymer is as definedin claim 11, and from 0.2 to 0.3 parts by weight of water are mixed for1 part by weight of water together with solvent B.
 29. The processaccording to claim 26 or 27, wherein the solvent B is THF, themultiblock copolymer is as defined in claim 11, and from 0.3 to 0.7,preferably 0.3 to 0.6, parts by weight of water are mixed for 1 part byweight of water together with solvent B.
 30. The process according toclaim 26 or 27, wherein the solvent B is THF, the multiblock copolymeris as defined in claim 13, and from 0.1 to 0.3, preferably 0.3 to 0.6,parts by weight of water are mixed for 1 part by weight of watertogether with solvent B.
 31. A solution, useful for preparingdispersions, capsules, vesicles, or the like, comprising: awater-miscible solvent B, a multiblock copolymer comprising at least twoblocks, block A and block B, wherein: block A is hydrophilic, soluble inwater and in the water-miscible solvent, block B is hydrophobic, solublein the water-miscible solvent, and block B is not soluble in water, alinear polymer H, soluble in the water-miscible solvent, and not solublewater, and optionally, an active ingredient, a reactive compound to betransformed by a chemical reaction, or a compound to be removed from aliquid phase, said ingredient or compound being soluble or dispersiblein solvent B, wherein block B and polymer H comprise repetitive units,said repetitive units being the same.
 32. A solution according to claim30, wherein solvent B is ethanol or THF, and the multiblock copolymer isas defined in claim
 11. 33. A solution according to claim 31, whereinsolvent B is THF, and the multiblock copolymer is as defined in claim13.